Visually the show is a lot cleaner and more refined, which might not be to some people's liking given how the rougher outlines and deeper colors of the previous season definitely added to the show's intensity, but it still is a great looking show with plenty of gorgeous fights and great character animation.
Perhaps if there's one big thing I think is a downgrade from season 1, it's the soundtrack. The general sound design of the fights is still present, but New Challenger's OST pales in comparison to Imahori's OST from season 1. It's still good, and the new emphasis on orchestral tracks certainly give the fights a more grand feel, fitting of the higher stakes, but the raw primal heat and speed of Imahori's tracks would definitely help out the show a lot I think.
Other than that, it's more Ippo, and you really can't go wrong with more Ippo.
